Air compressors

[Cobrabill]

I'm looking at up-grading my air compressor and have several choices:

A)60 gallon/2-stage/8 SCFM@100 psi/8.4SCFM@175psi/240volt/hard wired/max pressure-175
B)60 gallon/single stage/12.4SCFM@40psi/10.2SCFM@90psi/240volt/hard wired/Max pressure 150.

C)25 gallon/2-stage/5.6 SCFM@40psi/5.1SCFM@90psi/120 volt/portable

Thoughts?Comments?Single vs two stage-pro's/cons?

[DAVID GAGNARD]

My opinion;

When it comes to air compressors, BIGGER is always better......Opt for the biggest capacity tank, you can never have too much volume and two stage over single stage, no comparison.....upright takes up less room and easier to keep the tank drained of water.......

Good commercial units will last your lifetime and your kids and your grandkids will use the same compressor.........

The body shop I worked in has a Gilbarco, bought new in 1973,runs all day, 5 days a week, from 7:30 am to 5:00pm, still running today....we changed the oil and air filter once a year whether it needed it or not....electric motors (5hp) usually lasted about 3 years.....60 gallon upright tank....

I have a similar unit in my shop at home and it runs about the same amount in one month as the body shop unit does in 2 days.......should last another 50 to 75 years!!!!!!!!!!!!!

David

[601HP]

I agree with David Gagnard. I have owned an Ingersoll-Rand 60 gal. upright, two-stage, 5 horsepower compressor for 4 years. Its awesome. Recovery time is fairly fast when using air-hungry tools. This is an advantage of the two-stage. Have plenty of muscle with you when handling it. Mine weighs about 400 pounds.

One of these will sting the pocket-book, but once its in your garage, wired and plumbed in, you'll love it. Mine is plumbed into a LEGACY 50' recoiling hose unit suspended from the ceiling. Its proven to be a nice combination.

I used to have a 20-gal. Sears unit. It served its purpose but I am so glad its gone, especially the screaming noise it made. Also, it was advertised to be 120v or 240v. It would never completely fill when plugged into a 120v source. I had to use 240v.

As Ron61 says below, make your purchase based on your anticipated needs. Airing tires and such definitely will not warrant the expense of a large unit. But, if you consider grinding, cutting, polishing, buffing etc., the bigger machines are the ONLY way to go. I have a 7" dia. DA buffer that can almost keep my Ingersoll-Rand in recovery mode the entire time I use the buffer.

David

[Ron61]

Bill,

I agree completely with the two above posts.I have a smaller Sears unit that has wheels and I can move it where I want it, but it won't run air tools very well, plus it takes up more space as they said. But when I was getting mine, I have had it 7 years now, all I wanted was one that I could use to air up tires and blow things out and not have to lug everything to the garage. So this one has served my purpose very well, but if I were to ever get another it would most likely be the biggest upright that I could find space to put it and definitely a two stage. I almost bought an upright when I got mine, but I would need 200'of hose to get to some of the things that I use it for and I don't need more than the 120 pounds of pressure it will hold.

Ron

[vettestr]

Bill,
Add my vote to the 2 stage, 240 volt list. Another choice is the actual compressor type. If you plan to work her hard my personal choice is the older style cast iron case with crank case oil and real piston rings. Heat is the main reason for this choice as it is a dry heat here in AZ. The oil-less type uses a Teflon beer can for the cylinder liner as well as Teflon or some kinda plastic piston ring (only has 1 ring per piston) that simply does not last very long. Many of the oil-less type have the motor built into the comp. case and the motor is not serviceable.

The stand alone 240 volt motor, 2 stage oil in the crankcase dinosaur will last forever and is repairable if ever needed. Use the tank from the compressor you are replacing as an air storage tank rather than just pitching it. Have fun Bill.

[FWB]

go with the two stage operating at 175 psi it is the norm for industrial usage
i run my cnc's with those specs. it wont cycle as much during duty, if you plan
on using any air tools it will be alot more friendly. stay away from aluminum cly,
they just dont last. buy from a company that services them for industry. when
something goes wrong you get alot more mileage in getting it fixed.

Fred


http://www.origincorp.net/

heres the brand i have, mines 10hp 120 gal
http://www.gerardaircompressors.com/compair_kellogg.htm

[Fastz06]

Bigger is better....especially for compressors

I bought this.....

http://www.eatoncompressor.com/catal...747/206953.htm

They had good reviews on various sites. I'm satisfied so far.

[Snakebit]

ingersol rand 5 hp, 60 gal tank, 150 psi, 15.8 cfm runs about $900 to $1000 bucks. It's enough to run a Sata Jet 2000 spray gun which is an air hog, and any air tool you can throw in.

[DAVID GAGNARD]

The more/bigger compressor you end up with, the more bigger air tools you will end up buying........

My first compressor was a little Sears unit on wheels, served the purpose, till I ended up with more air tools than electric tools..Bought my compressor from a shop, it had been taken apart for a re-build, why, I have no idea, it needed nothing, bought everything in a box for $150.00, spent another $55.00 on a rebuild kit and about 125 bucks for a 5hp electric motor......

I plumbed my shop with 1 1/2inch plastic pipe, with 6 outlets, three of the six have 50 feet of air hose on them, two are capped for possible future use and one line goes directly to my bead blast cabinet (something everyone with a big compressor should have)....regular old PVC water line will work, it's rated for 300 psi and my compressor is set on 160 psi, I think...

I would highly recommend plumbing a shop with a number of outlets, makes working so much easeir and it's not hard to do...........

David

[PaulProe]

Bill,
Two stage is necessary to get to 150-175 psi. Unless you have an in-ground lift or a tire changer, there is little need for that high of pressure. Most air tools call for regulation to 90-100 psi which a single stage will do.

Smaller compressors (up to 5hp) generally are single stage since it gets more air with less horsepower.

Most industrial types over 5HP are two stage. Don't be fooled by HP. The government actually came down on the industry, making them recall a bunch of mis-labeled units. The most important factor is output (CFM) at a standard pressure (generally 100psi). Some use "90psi" so their output CFM appears higher. It really becomes a marketing game.

There are some cheap units out there - you get what you pay for. Anything less than $1,000 is definitely not industrial grade.

Paul

[vettestr]

Paulproe wrote =
"Bill,
Two stage is necessary to get to 150-175 psi. Unless you have an in-ground lift or a tire changer, there is little need for that high of pressure. Most air tools call for regulation to 90-100 psi which a single stage will do."

Paul and Bill,
The issue of a single stage or a 2 stage compressor is just as you mentioned. Most tools need a supply pressure of about 100 PSI. Your holding tank is full at 120 PSI verse the same volume tank starting at 175 PSI..... I guess in the end it depends on what you will be using it for, but a single stage will run much harder if not constantly to run many tools. I refuse to keep taking a brake to wait for the tank to fill up again and again.

[FWB]

exactly..................

[DAVID GAGNARD]

I have no idea what the cfm output of mine is, but as stated it is important... My compressor is an American Kellog 2-stage compressor on a 60 galoon tank. I've got it set (I think) to kick on at 120 psi and off at about 160 psi......I can run any air tool I have and have quite a few big uns, and my bead blast cabinet (pretty big also, 4'x2.5'x2') and it will cycle on and off, I can't ever remember running anything that required it to run constanly or for me to have to wait on it.........

It also uses a 5 hp motor, motor ratings can be somewhat misleading, but on a compressor this size, 5hp would be the minimum........

My compressor is at least 25 years old, possibly up to 35 years old......I've seen comparable units in the $1200.00 range, smaller compressors on 60 gallon tanks can go for around 1000 bucks and would be fine for a home shop...

Only thing I wish was mine was an upright instead of a horizontal unit...

I missed a deal last month on a similar but upright unit, used, no electric motor, sold for a measly 250 bucks!!!!!!!! got there about 2 hours too late.....shop around and you may find a used unit for a steal, I see them every now and then....

I've bought about 10 over the years, cleaned then up,painted them, maybe changed a fitting or two and double or tripled my money on everyone!!!!!!!!!!!!!!!!!!

David

[Fastz06]

Do NOT use plastic pipe to distribute air.....You will get terrible moisture in your air lines.

I've done it both ways and condensation is nearly zero with metal piping.

Check this out

http://www.tptools.com/StaticText/ai...ng-diagram.pdf

[Slither]

Curtis has a line of Rotary Screw Compressors which run very quietly when operating. Check them out at www.garage-pak.com. They also have a line on garage air piping that could be helpful.

Good luck to you.

[FWB]

do not buy a rotary screw type for shop use they are constant duty....
meaning they run all the time. they are for high cfm usage, really high, they require high maintenance. and will cause issues without other accessories such
as an intercooled dryer. plastic pipe is a no-no for compressed air. steel is best
copper works and is easier to plumb. my compressor is the life-blood of my business without it i am done. in ten years i have:
1. changed the oil yearly
2 changed the air filters yearly
3 had no break downs

note mine is located in an unheated portion of the shop it doesnt care. it runs
at low of 100psi shuts down at high of 160psi steel plumbing from compressor
to main regulator then copper to each leg each leg has its own filter-dryer with
replaceable element. i regulate 90 psi to shop and never ran out of cfm.

Fred

[Slither]

Originally Posted by FWB

do not buy a rotary screw type for shop use they are constant duty....
meaning they run all the time. they are for high cfm usage, really high, they require high maintenance. and will cause issues without other accessories such
as an intercooled dryer. plastic pipe is a no-no for compressed air. steel is best
copper works and is easier to plumb. my compressor is the life-blood of my business without it i am done. in ten years i have:
1. changed the oil yearly
2 changed the air filters yearly
3 had no break downs

note mine is located in an unheated portion of the shop it doesnt care. it runs
at low of 100psi shuts down at high of 160psi steel plumbing from compressor
to main regulator then copper to each leg each leg has its own filter-dryer with
replaceable element. i regulate 90 psi to shop and never ran out of cfm.

Fred

Good to know, Fred!

[Cobrabill]

Let's not get into the plastic vs metal piping thing again.The biggest workout is going to be a DA for sanding.I guess it's gonna be the 60 gallon/240/volt.THe single stage is rated at 150 psi and the two stage is rated at 175 psi.I guess the longevity is worth the 25 lb less pressure.

[FWB]

didnt know there's previous discussion on plastic vs. steel. from an industrial
standpoint if you bump into a plastic line its oh-no right away, with steel it'll
take more of a lickin'. compressed air can kill you!........90psi will cut thru the skin, one air bubble in your artery its good-bye. i'm not sure OSHA would like it either but OSHA isnt monitoring your house.
here are some advertised stats:

Compressed Air Precautions

Compressed air is quite handy around a work area, but it can be dangerous if not used properly.

Dangers of Compressed Air:

1. A blast of air under 40 p.s.i from 4 inches away can rupture an eardrum or cause brain damage.
2. As little as 12 p.s.i can pop an eyeball from its socket.
3. Air can enter the navel, even through a layer of clothing, and inflate and rupture the intestines.
4. Directed at the mouth, compressed air can rupture the lungs.

The following guidelines will reduce the risk of injury when using compressed air:

1. Examine all hoses, connections, and equipment to see that they are in good condition before turning the pressure on.
2. Never point the air hose nozzle at any part of your body or at any other person.
3. Never look into the end of a compressed air device.
4. Never use compressed air to blow dust or dirt off clothing or body parts.
5. No horseplay with air hose.
6. Never kink the hose to stop airflow - turn it off at the control valve.
7. When using air for cleaning, make sure the pressure is no higher than 30 p.s.i.
8. Always wear eye protection when using compressed air.

[601HP]

Cobrabill:

Lots of info on this site. It provides a lot of fact instead of opinion.

http://www.northerntool.com/catalog/...ircompressors/

Also, when a compressor stores air at 150 or 175 psi, this will add to the volume of stored air, thus reducing the recovery cycling time. However, the regulator typically distributes air to your tools at a maximum of only about 110 or so psi. I am not referring to industrial applications.